Chapter 2: QUIZ

Select the statement about mixtures that is correct. A) A solution contains solvent in large amounts and solute in smaller quantities. B) Solutions contain particles that settle out in time. C) Suspensions can change reversibly from liquid to solid. D) Suspensions are homogeneous mixtures of two or more components.

A) A solution contains solvent in large amounts and solute in smaller quantities.

Which statement about enzymes is false? A) Enzymes raise the activation energy needed to start a reaction. B) Enzymes are composed mostly of protein. C) Enzymes are organic catalysts. D) Enzymes may be damaged by high temperature.

A) Enzymes raise the activation energy needed to start a reaction.

Select the correct statement about isotopes. A) Isotopes of the same element have the same atomic number but differ in their atomic masses. B) All the isotopes of an element have the same number of neutrons. C) All the isotopes of an element are radioactive. D) Isotopes occur only in the heavier elements.

A) Isotopes of the same element have the same atomic number but differ in their atomic masses.

What does CH4 mean? A) There is one carbon and four hydrogen atoms. B) There are four carbon and four hydrogen atoms. C) This is an inorganic molecule. D) This was involved in a redox reaction.

A) There is one carbon and four hydrogen atoms.

Choose the answer that best describes HCO3-. A) a bicarbonate ion B) common in the liver C) a weak acid D) a proton donor

A) a bicarbonate ion

A solution that has a pH of 2 could best be described as being ________. A) acidic B) basic C) neutral D) slightly acidic

A) acidic

What happens in redox reactions? A) both decomposition and electron exchange occur B) the electron acceptor is oxidized C) the electron donor is reduced D) the reaction is always easily reversible

A) both decomposition and electron exchange occur

Select which reactions will usually be irreversible regarding chemical equilibrium in living systems. A) glucose to CO2 and H2O B) ADP + Pi to make ATP C) H2O + CO2 to make H2CO3 D) glucose molecules joined to make glycogen

A) glucose to CO2 and H2O

Salts are always ________. A) ionic compounds B) single covalent compounds C) double covalent compounds D) hydrogen bonded

A) ionic compounds

Which of the following describes coenzymes? A) organic molecules derived from vitamins B) two enzymes that perform the same function C) metal ions D) enzymes that work together

A) organic molecules derived from vitamins

What is a chain of 25 amino acids called? A) polypeptide B) nucleotide C) protein D) starch

A) polypeptide

Amino acids joining together to make a peptide is a good example of a(n) ________ reaction. A) synthesis B) decomposition C) exchange D) reversible

A) synthesis

A chemical reaction in which bonds are broken is usually associated with ________. A) the release of energy B) the consumption of energy C) a synthesis D) forming a larger molecule

A) the release of energy

The ________ molecule directly provides energy for cellular work.

ATP

Select the most correct statement regarding nucleic acids. A) Three forms exist: DNA, RNA, and tDNA. B) DNA is a long, double-stranded molecule made up of A, T, G, and C bases. C) RNA is a long, single-stranded molecule made up of the bases A, T, G, and C. D) TDNA is considered a molecular slave of DNA.

B) DNA is a long, double-stranded molecule made up of A, T, G, and C bases.

Which bonds often bind different parts of a molecule into a specific three-dimensional shape? A) Carbon B) Hydrogen C) Oxygen D) Amino acid

B) Hydrogen

Which of the following is true regarding the concentration of solutions? A) Percent solutions are parts per 1000 parts. B) Molarity is one mole of solute per 1000 ml of solution. C) To calculate molarity, one must know the atomic number of the solute. D) To calculate molarity, one must know the atomic weight of the solvent.

B) Molarity is one mole of solute per 1000 ml of solution.

What does the formula C6H12O6 mean? A) There are 6 calcium, 12 hydrogen, and 6 oxygen atoms. B) There are 12 hydrogen, 6 carbon, and 6 oxygen atoms. C) The molecular weight is 24. D) The substance is a colloid.

B) There are 12 hydrogen, 6 carbon, and 6 oxygen atoms.

What is a dipole? A) a type of bond B) a polar molecule C) a type of reaction D) an organic molecule

B) a polar molecule

Choose the answer that best describes fibrous proteins. A) rarely exhibit secondary structure B) are very stable and insoluble in water C) are usually called enzymes D) are cellular catalysts

B) are very stable and insoluble in water

Sucrose is a ________. A) monosaccharide B) disaccharide C) polysaccharide D) triglyceride

B) disaccharide

Which property of water is demonstrated when we sweat? A) high heat capacity B) high heat of vaporization C) polar solvent properties D) reactivity E) cushioning

B) high heat of vaporization

Which protein types are vitally important to cell function in all types of stressful circumstances? A) structural proteins B) molecular chaperones C) catalytic proteins D) regulatory proteins

B) molecular chaperones

Which of the following constitutes a long chain of simple sugars? A) monosaccharide B) polysaccharide C) protein D) nucleic acid

B) polysaccharide

An example of a coenzyme is ________. A) copper B) riboflavin (vitamin B2) C) iron D) zinc

B) riboflavin (vitamin B2)

What level of protein synthesis is represented by the coiling of the protein chain backbone into an alpha helix? A) primary structure B) secondary structure C) tertiary structure D) quaternary structure

B) secondary structure

The genetic information is coded in DNA by the ________. A) regular alteration of sugar and phosphate molecules B) sequence of the nucleotides C) three-dimensional structure of the double helix D) arrangement of the histones

B) sequence of the nucleotides

In a DNA molecule, the phosphate serves ________. A) as a code B) to hold the molecular backbone together C) to bind the sugars to their bases D) as nucleotides

B) to hold the molecular backbone together

________ have a bitter taste, feel slippery, and are proton acceptors.

Bases

An atom with a valence of 3 may have a total of ________ electrons. A) 3 B) 8 C) 13 D) 17

C) 13

What is the ratio of fatty acids to glycerol in neutral fats? A) 1:1 B) 2:1 C) 3:1 D) 4:1

C) 3:1

Atom X has 17 protons. How many electrons are in its valence shell? A) 3 B) 5 C) 7 D) 10

C) 7

Which of the following is not an electrolyte? A) HCl B) Ca2CO3 C) H2O D) NaOH

C) H2O

Which of the following statements is false? A) Chemical reactions proceed more quickly at higher temperatures. B) Chemical reactions progress at a faster rate when the reacting particles are present in higher numbers. C) Larger particles move faster than smaller ones and thus collide more frequently and more forcefully. D) Catalysts increase the rate of chemical reactions.

C) Larger particles move faster than smaller ones and thus collide more frequently and more forcefully.

Which of the following is not true of proteins? A) They may be denatured or coagulated by heat or acidity. B) Some types are called enzymes. C) They appear to be the molecular carriers of the coded hereditary information. D) Their function depends on the three-dimensional shape.

C) They appear to be the molecular carriers of the coded hereditary information.

The four elements that make up about 96% of body matter are ________. A) carbon, oxygen, phosphorus, calcium B) nitrogen, hydrogen, calcium, sodium C) carbon, oxygen, hydrogen, nitrogen D) sodium, potassium, hydrogen, oxygen

C) carbon, oxygen, hydrogen, nitrogen

The single most abundant protein in the body is ________. A) DNA B) hemoglobin C) collagen D) glucose

C) collagen

In liquid XYZ, you notice that light is scattered as it passes through. There is no precipitant in the bottom of the beaker, though it has been sitting for several days. What type of liquid is this? A) solution B) suspension C) colloid D) mixture

C) colloid

Carbohydrates are stored in the liver and muscles in the form of ________. A) glucose B) triglycerides C) glycogen D) cholesterol

C) glycogen

Carbohydrates and proteins are built up from their basic building blocks by the ________. A) addition of a water molecule between each two units B) addition of a carbon atom between each two units C) removal of a water molecule between each two units D) removal of a nitrogen atom between each two units

C) removal of a water molecule between each two units

The chemical symbol OO means ________. A) zero equals zero B) both atoms are bonded and have zero electrons in the outer orbit C) the atoms are double bonded D) this is an ionic bond with two shared electrons

C) the atoms are double bonded

The numbers listed represent the number of electrons in the first, second, and third energy levels, respectively. On this basis, which of the following is an unstable or reactive atom? A) 2, 8, 8 B) 2, 8 C) 2 D) 2, 8, 1

D) 2, 8, 1

If atom X has an atomic number of 74 it would have which of the following? A) 37 protons and 37 neutrons B) 37 electrons C) 74 protons D) 37 protons and 37 electrons

D) 37 protons and 37 electrons

Choose the statement that is false or incorrect. A) In chemical reactions, breaking old bonds requires energy and forming new bonds releases energy. B) Exergonic reactions release more energy than they absorb. C) Endergonic reactions absorb more energy than they release. D) A key feature of the body's metabolism is the almost exclusive use of exergonic reactions by the body.

D) A key feature of the body's metabolism is the almost exclusive use of exergonic reactions by the body.

Which of the following would be regarded as an organic molecule? A) H2O B) NaCl C) NaOH D) CH4

D) CH4

Which of the following is a neutralization reaction? A) HCl → H+ + Cl- B) NaOH → Na+ + OH- C) NH3 + H+ → NH4+2 D) HCl + NaOH → NaCl + H2O

D) HCl + NaOH → NaCl + H2O

Which of the following elements is necessary for proper conduction of nervous impulses? A) Fe B) I C) P D) Na

D) Na

________ is fat soluble, produced in the skin on exposure to UV radiation, and necessary for normal bone growth and function. A) Vitamin K B) Cortisol C) Vitamin A D) Vitamin D

D) Vitamin D

In general, the lipids that we refer to as oils have ________. A) a high water content B) long fatty acid chains C) a high degree of saturated bonds D) a high degree of unsaturated bonds

D) a high degree of unsaturated bonds

Which of the following is an example of a suspension? A) cytoplasm B) salt water C) rubbing alcohol D) blood

D) blood

Heat shock proteins (hsp) are a type of protein called ________. A) coenzymes B) cofactors C) eicosanoids D) chaperonins

D) chaperonins

Two good examples of a colloid would be Jell-O® and ________. A) blood B) toenails C) urine D) cytosol

D) cytosol

Which of the following does not describe the ATP molecule? A) chemical work B) mechanical work C) transport D) pigments

D) pigments

Which of the following is the major positive ion outside cells? A) nitrogen B) hydrogen C) potassium D) sodium

D) sodium

Which of the following is not considered a factor in influencing a reaction? A) temperature B) concentration C) particle size D) time

D) time

Which of the following is not a role of molecular chaperonins? A) prevent accidental, premature, or incorrect folding of polypeptide chains B) aid the desired folding and association process of polypeptides C) help to translocate proteins and certain metal ions across cell membranes D) promote the breakdown of damaged or denatured proteins E) act as a biological catalyst

E) act as a biological catalyst

A dipeptide can be broken into two amino acids by dehydration synthesis.

FALSE

About 60% to 80% of the volume of most living cells consists of organic compounds.

FALSE

Chemical properties are determined primarily by neutrons.

FALSE

Covalent bonds are generally less stable than ionic bonds.

FALSE

Hydrogen bonds are comparatively strong bonds.

FALSE

Isotopes differ from each other only in the number of electrons contained.

FALSE

Lipids are a poor source of stored energy.

FALSE

A charged particle is generally called an ion.

TRUE

A molecule consisting of one carbon atom and two oxygen atoms is correctly written as CO2.

TRUE

All organic compounds contain carbon.

TRUE

Alpha particles, although relatively weak energy particles, are second only to smoking as a cause of lung cancer.

TRUE

Buffers resist abrupt and large changes in the pH of the body by releasing or binding ions.

TRUE

Current information theorizes that omega-3 fatty acids decrease the risk of heart disease.

TRUE

Emulsions and colloids are the same thing.

TRUE

Glucose is an example of a monosaccharide.

TRUE

Mixtures are combinations of elements or compounds that are physically blended together but are not bound by chemical bonds.

TRUE

No chemical bonding occurs between the components of a mixture.

TRUE

The atomic weight is only an average of relative weights of an atom and its isotopes, and it may vary from the weight of a specific isotope.

TRUE

The fact that no chemical bonding occurs between the components of a mixture is the chief difference between mixtures and compounds.

TRUE

The lower the pH, the higher the hydrogen ion concentration.

TRUE

The pH of body fluids must remain fairly constant for the body to maintain homeostasis.

TRUE

Hydrogen bonds are more like a type of weak ________ than true bonds.

attraction

Weak acids and bases make good ________.

buffers

A holoenzyme is composed of an apoenzyme and a(n) ________.

cofactor

Molecules such as methane that are made of atoms that share electrons have ________ bonds.

covalent

In a DNA molecule, guanine would connect to ________.

cytosine

AB → A + B is an example of a(n) ________ reaction.

decomposition

Starch is the stored carbohydrate in plants, while ________ is the stored carbohydrate in animals.

glycogen

Which metals have a toxic effect on the body?

heavy

An atom with three electrons would have a valence of ________.

one

How many phosphates would AMP have attached to it?

one

The atomic number is equal to the number of ________.

protons (and electrons)